package com.maben.utils;

import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.util.Enumeration;
 
/**
 * 获取IP 工具类
 */
public class NetUtil {
    public static String INTRANET_IP = getIntranetIp(); // 内网IP
    public static String INTERNET_IP = getInternetIp(); // 外网IP
 
    private NetUtil(){}
 
    /**
     * 获得内网IP
     * @return 内网IP
     */
    private static String getIntranetIp(){
        try{
            return InetAddress.getLocalHost().getHostAddress();
        } catch(Exception e){
            throw new RuntimeException(e);
        }
    }
 
    /**
     * 获得外网IP
     * @return 外网IP
     */
    private static String getInternetIp(){
        try{
            Enumeration<NetworkInterface> networks = NetworkInterface.getNetworkInterfaces();
            InetAddress ip = null;
            Enumeration<InetAddress> addrs;
            while (networks.hasMoreElements())
            {
                addrs = networks.nextElement().getInetAddresses();
                while (addrs.hasMoreElements())
                {
                    ip = addrs.nextElement();
                    if (ip instanceof Inet4Address
                            && ip.isSiteLocalAddress()
                            && !ip.getHostAddress().equals(INTRANET_IP))
                    {
                        return ip.getHostAddress();
                    }
                }
            }
 
            // 如果没有外网IP，就返回内网IP
            return INTRANET_IP;
        } catch(Exception e){
            throw new RuntimeException(e);
        }
    }
 
    /**
     * 获得指定网卡IP
     * @return IP
     */
    public static String getInternetIp(String type){
        try{
            final Enumeration<NetworkInterface> networks = NetworkInterface.getNetworkInterfaces();
            while (networks.hasMoreElements()){
            	final NetworkInterface ni = (NetworkInterface) networks.nextElement();
                final String niName = ni.getName();
                if (!niName.equals(type)) {
                    continue;  
                } else {  
                    Enumeration<?> e2 = ni.getInetAddresses();  
                    while (e2.hasMoreElements()) {  
                        InetAddress ia = (InetAddress) e2.nextElement();  
                        if (ia instanceof Inet6Address)
                            continue;  
                        return ia.getHostAddress();  
                    }  
                }
            }
            // 如果没有外网IP，就返回内网IP
            return INTRANET_IP;
        } catch(Exception e){
            throw new RuntimeException(e);
        }
    }

    public static void main(String[] args){
        System.out.println("内网IP:"+NetUtil.INTRANET_IP);
        System.out.println("外网IP:"+NetUtil.INTERNET_IP);
        if (args.length>0) {
            System.out.println("外网IP2:" + NetUtil.getInternetIp(args[0]));
        }
    }

}